This invention relates to a port structure used with containers for holding or passing sterile fluids or biological materials, and a method for making the same.
At the present time there are numerous medical and scientific practices which require the sterile transfer of fluids or other biological materials from one container to another. The state of the art is such, however, that no true sterile method for joining separate containers to facilitate the sterile transfer of fluids is available. Thus, where a sterile transfer from one container to another is required, it is often accomplished by prejoining the containers together and then sterilizing the entire assembly. This method is not entirely satisfactory because it necessitates the handling of cumbersome prejoined units, and involves additional costs associated with prejoined containers.
When prejoined units are impracticable, separate containers are generally connected by means of a sterile transfer set. Such a transfer set includes a pair of plastic couplers which are adapted to pierce and penetrate the corresponding containers to be joined. Once the transfer set is removed from its sterilized package, however, the plastic couplers are susceptible to contamination from airborne bacteria. As a result, a sterile connection cannot be assured. Moreover, as a general rule, a sterile transfer set can be correctly used only by persons who have had proper training.
The method and apparatus of the invention achieves a true sterile connection which can be accomplished with only a minimal amount of training and skill. More particularly, the apparatus of the invention includes a port structure comprising a flexible thermoplastic sleeve heat sealed to any fluid passage means such as a container, and a thermoplastic tube secured to the sleeve to form an extension thereof. Though this thermoplastic tube is hereinafter characterized as "rigid," that term, as used herein, should not be construed synonymously with "brittle," but is intended to describe a structure having sufficient stiffness to maintain its shape under its own weight. The rigid tube has a free end extending beyond the sleeve which is adapted to be joined to the free end of a second rigid tube extending from a sleeve. This second rigid tube and second flexible sleeve comprise a second port structure secured to a second container. Preferably secured near the outer end of each rigid tube is a thermoplastic diaphragm which initially seals off each free end and is subsequently melted open just prior to joining the rigid tubes together in order to effect a sterile connection between the first and second containers.
Sterile joinder of the two containers is achieved by bringing the first and second rigid tubes into alignment and softening the facing ends thereof, preferably through the application of heat. During this heating process, the thermoplastic diaphragms which previously sealed off each rigid tube are softened, and ultimately melted open. The facing ends of the rigid tubes are then brought into contact and hardened preferably by holding the ends together under a slight pressure while the thermoplastic tubes cool and solidify. Upon solidification, a a permanent connection is formed thereby permitting fluid transfer between the two containers.